Devices of today are often time based and perform tasks, respond to events, perform maintenance, take measurements, generate log entries and the like based on time. To perform these tasks, the device needs to incorporate some type of persistent clock, generally referred to as a real time clock. The real time clock is responsible to provide time information within an acceptable accuracy range.
The real time clock includes an oscillator and is typically powered by a main source of power. For example, in a personal computer, the real time clock is powered by power supply that converts AC power to a suitable power level. However, if the main source of power becomes inoperable, the oscillator may stop working and the real time clock can lose its clock information. As a result, the device operation can degrade and/or fail.
One technique to account for loss of the main source of power is to provide a backup battery. This battery is configured to supply power to the real time clock in the event that the main source of power is off. The battery permits operation of the oscillator until the main source of power is turned back ON.
However, including a battery can be expensive and difficult to include in a device.